7. Tammy is energized every time she gets to interact a lot with others. According to Jung's typology system, Tammy is A. a feeler.
B. a sensor
Can introvert.
D. an extrovert

Which of these is a disadvantage of hydrogen fuel cells? a. engines that use hydrogen fuel are more efficient than gasoline-powered engines. b. the only emission produced by hydrogen fuel cells is water. c. hydrogen fuel is continually available and useful for heating. d. hydrogen fuel is often purified in a process that emits lots of greenhouse gases.